Frequency steered sonar array orientation

ABSTRACT

A transducer assembly comprises a housing and a plurality of frequency steered transducer array elements. Each of the transducer array elements includes a plurality of piezoelectric elements. The frequency steered transducer array elements are configured to receive a transmit electronic signal including a plurality of frequency components and to transmit an array of sonar beams into a body of water. Each sonar beam is transmitted in an angular direction that varies according to one of the frequency components of the transmit electronic signal. The frequency steered transducer array elements are positioned within the housing in a fan-shaped configuration where an end section of at least two of the frequency steered transducer array elements are within an intersection range of each other.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit under 35 U.S.C. § 119(e) ofU.S. Provisional Application Ser. No. 62/407,335, entitled FREQUENCYSTEERED SONAR ARRAY ORIENTATION, filed on Oct. 12, 2016. U.S.Provisional Application Ser. No. 62/407,335 is herein incorporated byreference in its entirety.

BACKGROUND

Traditional recreational scanning sonar systems are often incapable ofgenerating real-time sonar imagery. For example, sidescan sonar systemsgenerate useful imagery only when attached to a moving boat. This can beproblematic for fishermen, whose vessels may remain stationary forextended periods of time while fishing. And, although some sonar systemsare capable of generating real-time sonar imagery, these systems areincapable of generating the historical sequence of images to which manyfisherman are accustomed. Existing frequency steered sonar systems areoften sized and configured in an undesirable manner for boat (transom)or tolling motor mounting.

Frequency steered sonar arrays have been utilized to provide highquality imaging at near video framerates in the underwater explorationand surveying industries. The advantage of frequency steered sonararrays over alternative techniques such as phased arrays is the minimalhardware cost required to drive and sample frequency steered arrays. Thetradeoff is that multiple frequency steered arrays must be used incoordination to achieve continuous wide field of views.

SUMMARY

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the detaileddescription. This summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter. Other aspectsand advantages of the present technology will be apparent from thefollowing detailed description of the embodiments and the accompanyingdrawing figures.

Embodiments of the present technology provide a transducer assemblycomprising a housing and a plurality of frequency steered transducerarray elements. Each of the transducer array elements includes aplurality of piezoelectric elements. The frequency steered transducerarray elements are configured to receive a transmit electronic signalincluding a plurality of frequency components and to transmit an arrayof sonar beams into a body of water. Each sonar beam is transmitted inan angular direction that varies according to one of the frequencycomponents of the transmit electronic signal. The frequency steeredtransducer array elements are positioned within the housing in afan-shaped configuration where an end section of at least two of thefrequency steered transducer array elements are within an intersectionrange of each other.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description is described with reference to the accompanyingfigures. The use of the same reference numbers in different instances inthe description and the figures may indicate similar or identical items.

FIG. 1 is a front perspective view of a marine sonar display deviceconstructed in accordance with various embodiments of the presenttechnology;

FIG. 2 is a schematic block diagram of at least a portion of thecomponents of the marine sonar display device also illustrating that themarine sonar display device interfaces with a frequency steered sonarelement;

FIG. 3 is a side view of a marine vessel utilizing the marine sonardisplay device and the frequency steered sonar element, with the sonarelement configured to transmit a first sonar wedge into the water in aforward direction and a second sonar wedge in a downward direction;

FIG. 4 is a front view of the marine vessel utilizing the marine sonardisplay device and the frequency steered sonar element, with the sonarelement configured to transmit a first sonar wedge into the water in aport direction and a second sonar wedge in a starboard direction;

FIG. 5 is a schematic block diagram of at least a portion of thecomponents of electronic circuitry that may be utilized with the marinesonar display device to process signals from the frequency steered sonarelement;

FIG. 6 is a screen capture taken from the display of the marine sonardisplay device presenting a forward-projecting near real time sonarwedge image and a downward-projecting near real time sonar wedge image;

FIGS. 7A and 7B are screen captures taken from the display of the marinesonar display device presenting near real time sonar wedge images in afirst window and a historical sonar image in a second window with thehistorical sonar image of FIG. 7A scrolling left to create thehistorical sonar image of FIG. 7B;

FIG. 8 is a screen capture taken from the display of the marine sonardisplay device presenting a forward-projecting near real time sonarwedge image, a spaced apart downward-projecting near real time sonarwedge image, and a historical sonar image positioned therebetween;

FIGS. 9A and 9B are screen captures taken from the display of the marinesonar display device presenting a forward-projecting near real timesonar wedge image and a downward-projecting near real time sonar wedgeimage, wherein there is a false artifact present in FIG. 9A which isremoved in FIG. 9B; and

FIGS. 10A and 10B are screen captures taken from the display of themarine sonar display device presenting a forward-projecting near realtime sonar wedge image and a downward-projecting near real time sonarwedge image, wherein the images of FIG. 10A are not edge filtered, whilethe images of FIG. 10B are edge filtered.

FIG. 11 is a diagram illustrating a field-of-view for an example sonartransducer assembly configured in accord with various embodiments of thepresent invention.

FIG. 12 is a perspective view of an example sonar transducer assembly,wherein the frequency steered transducer elements of the assembly arearranged end-to-end.

FIG. 13 is a schematic view of an example sonar transducer assembly,wherein the frequency steered transducer elements of the assembly arearranged in a fan-shaped configuration.

FIG. 14A is a diagram illustrating an exemplary field-of-view for thesonar transducer assembly of FIG. 12.

FIG. 14B is a diagram illustrating an exemplary field-of-view for thesonar transducer assembly of FIG. 13.

FIG. 15 is a perspective view of another example sonar transducerassembly including a plurality of frequency steered transducer elements.

FIG. 16 is a cross section of a housing of the example sonar transducerassembly of FIG. 13.

FIG. 17 is a perspective view of the housing of FIG. 16.

The drawing figures do not limit the present technology to the specificembodiments disclosed and described herein. The drawings are notnecessarily to scale, emphasis instead being placed upon clearlyillustrating the principles of the technology.

DETAILED DESCRIPTION

The following detailed description of the technology references theaccompanying drawings that illustrate specific embodiments in which thetechnology can be practiced. The embodiments are intended to describeaspects of the technology in sufficient detail to enable those skilledin the art to practice the technology. Other embodiments can be utilizedand changes can be made without departing from the scope of the presenttechnology. The following detailed description is, therefore, not to betaken in a limiting sense. The scope of the present technology isdefined only by the appended claims, along with the full scope ofequivalents to which such claims are entitled.

In this description, references to “one embodiment”, “an embodiment”, or“embodiments” mean that the feature or features being referred to areincluded in at least one embodiment of the technology. Separatereferences to “one embodiment”, “an embodiment”, or “embodiments” inthis description do not necessarily refer to the same embodiment and arealso not mutually exclusive unless so stated and/or except as will bereadily apparent to those skilled in the art from the description. Forexample, a feature, structure, act, etc. described in one embodiment mayalso be included in other embodiments, but is not necessarily included.Thus, the present technology can include a variety of combinationsand/or integrations of the embodiments described herein.

Conventional frequency-steered array systems, such as those disclosed inU.S. Pat. No. 8,811,120, which is incorporated herein by specificreference, require a stacked array configuration, where each of thesystem transducers arrays are stacked in an “X-configuration.” Suchconfigurations may be unsuitable for mounting to the underside of aboat, given its very wide and multi-faceted drag cross section. Forexample, laminar flow of water across the transducer is jeopardized bythe multiple angular facets in close proximity. The arrangement is notsymmetric with respects to left-right turns performed by the boat whichcan result in unpredictable handling and response. Any cavitation,bubbling, etc will interrupt the sound and thus impair sound imaging.

Embodiments of the present invention provide an improvedfrequency-steered array configuration, where the transducer arrays aremore desirably positioned to provide a field-of view like thatillustrated in FIG. 11. In configuration, the transducer assemblyprovided by embodiments of the present invention can be oriented on thebow-stern plane of a vessel, such as a boat. This allows the transducerassembly to stay in the water and to continue sonifying and imaging thescene even when the boat is in motion and “on plane”. Example transducerconfigurations described herein are suitable for boating use cases andprovide an assembly that is narrow in drag cross-section, symmetricleft-to-right, and with improved laminar flow.

Embodiments of the present technology may be utilized in combinationwith one or more of the following exemplary systems, features, and/orconfigurations of a marine sonar display device which interfaces with afrequency steered sonar element. The frequency steered sonar element mayreceive a transmit electronic signal from the marine sonar displaydevice, with the transmit electronic signal including a plurality offrequency components. The frequency steered sonar element may transmit acorresponding array of sonar beams into a body of water, wherein thearray of sonar beams forms a sonar wedge. Each sonar beam may have afrequency component determined by one of the frequency components of thetransmit electronic signal. Furthermore, each sonar beam may betransmitted in an angular direction that varies according to thefrequency component of the sonar beam. When the frequency steered sonarelement receives the reflections of the sonar beams, it may generate areceive electronic signal. The receive electronic signal includes aplurality of frequency components, wherein each frequency componentindicates the angular direction from which the reflections of the sonarbeams were received.

The marine sonar display device may receive the receive electronicsignal from the frequency steered sonar element. The marine sonardisplay device may then calculate an array of sonar data slices andgenerate an array of sonar image slices, wherein each sonar image sliceincludes sonar imagery from the reflections of one of the sonar beams.The marine sonar display device may display the array of sonar imageslices in near real time. The array of sonar image slices includes arepresentation of underwater objects and the water bed that were in thepath of the sonar wedge. The marine sonar display device maysimultaneously display a historical sequence of at least one of thesonar image slices from the array. The historical sequence may bescrolled on the display.

Embodiments of the technology will now be described in more detail withreference to the drawing figures. Referring initially to FIGS. 1 and 2,a marine sonar display device 10 is illustrated which is configured todisplay images of underwater objects and the water bed derived fromreflections of sonar beams generated by a frequency steered sonarelement 12. The marine sonar display device 10 broadly comprises ahousing 14, a display 16, a user interface 18, a communication element20, a location determining element 22, a memory element 24, and aprocessing element 26.

The frequency steered sonar element 12, as illustrated in FIGS. 3 and 4,may include one or more transducer elements or an array of transducerelements. Exemplary transducer elements may be formed from piezoelectricmaterials, like ceramics such as lead zirconate titanate (PZT) orpolymers such as polyvinylidene difluoride (PVDF), which may change itsdimension along one or more axes in response to an electronic signalapplied to the material. In a typical implementation, an oscillatingvoltage may be applied to the piezoelectric material resulting in thematerial generating a mechanical oscillation at the same frequency asthe oscillation of the voltage. In addition, the piezoelectric materialmay generate an oscillating electric voltage in response to oscillatingacoustic waves applying pressure to the material which changes thedimension along one or more axes. In some implementations, the frequencysteered sonar element 12 may include one or more individual transducerelements, wherein the faces of each transducer element are notnecessarily aligned with the faces of other transducer elements. Inother implementations, the frequency steered sonar element 12 mayinclude one or more transducer arrays, wherein each transducer arrayincludes a plurality of linearly-aligned transducer elements. Thetransducer arrays may be oriented in line with one another, parallel toone another, transverse to one another, or at any non-zero angle.

The frequency steered sonar element 12 may transmit a sonar beam 28 intoa body of water in response to receiving a transmit electronic signal.The transmit electronic signal may include one or more single-endedelectronic signals or one or more differential electronic signals. Thetype of electronic signal received by the frequency steered sonarelement 12 may depend upon its components and architecture. For example,one or more single-ended electronic signals may be communicated to oneor more individual transducer elements, while each half of one or moredifferential signals may be communicated to one transducer element in anarray of transducer elements or to one transducer element in each arrayof transducer elements. Certain characteristics of the sonar beam 28,such as a frequency or frequency component, may correspond to similarcharacteristics of the transmit electronic signal, such that the sonarbeam 28 is generated to include the same frequency component as afrequency component of the transmit electronic signal. The frequencysteered sonar element 12 may transmit the sonar beam 28 in an angulardirection with respect to the sonar element 12 which varies according tothe frequency component of the sonar beam 28. For example, a first sonarbeam 28 with a first frequency component may be transmitted in a firstangular direction, while a second sonar beam 28 with a second frequencycomponent may be transmitted in a second angular direction, and soforth.

During operation, the frequency steered sonar element 12 may receive atransmit electronic signal (from a device, such as the marine sonardisplay device 10 of the present technology) and in turn, may transmitan array of sonar beams 28. In some implementations, the transmitelectronic signal may include a sequence of spaced-apart-in-time pulses,wherein each pulse is an oscillating electrical voltage or electricalcurrent that includes one of a plurality of frequency components. Forexample, the transmit electronic signal may include a sequence of fourpulses, each including a different frequency component. In otherimplementations, the transmit electronic signal may include at least onebroadband pulse that includes a plurality of frequency components. As anexample, the broadband pulse may include four frequency components.

Typically, the frequency components of the transmit electronic signaland, in turn, the sonar beams 28 are chosen such that the generatedsonar beams 28 are adjacent to one another and the spacing between theangular directions of the sonar beams 28 ranges from less than 1 degreeto approximately 5 degrees. For example, the frequencies may be chosensuch that the frequency steered sonar element 12 transmits a first sonarbeam 28 with a first frequency component in an angular direction of 0degrees, a second sonar beam 28 with a second frequency component in anangular direction of 4 degrees, a third sonar beam 28 with a thirdfrequency component in an angular direction of 8 degrees, and so forth.In other instances, the sonar beams 28 may overlap one another withlittle spacing between center lines of the main lobes of each beam.Furthermore, it is noted that the listed angular directions are relativeand do not represent the absolute angular directions at which the sonarbeams 28 would be transmitted into the water. The relationship betweenthe frequency of the sonar beam 28 and the angular direction at whichthe sonar beam 28 is transmitted may vary according to the constructionof the frequency steered sonar element 12, the components used, thedimensions of the components, the properties of the materials used forthe components, and the like. An example of a transducer array that mayembody, or be included in, the frequency steered sonar element 12 isdisclosed in U.S. Pat. No. RE45379, which is hereby incorporated byreference into the current document.

The process of the frequency steered sonar element 12 receiving thetransmit electronic signal and transmitting a corresponding array ofsonar beams 28 may be known as a “sweep”, a “frequency sweep”, a “sonarbeam sweep”, etc. When a sweep occurs and an array of sonar beams 28 aretransmitted in adjacent angular directions, a sonar wedge 30 may beformed which includes the volume in the water covered by the adjacentsonar beams 28. FIGS. 3 and 4 show examples of the frequency steeredsonar element 12 in operation. FIG. 3 illustrates the frequency steeredsonar element 12 transmitting a first sonar wedge 30A in the forwarddirection and a second sonar wedge 30B in the downward direction, eachsonar wedge 30 being formed by an exemplary array of four sonar beams28, each transmitted with a different frequency component. The dashedlines in FIGS. 3 and 4 indicate the virtual boundaries of each sonarbeam 28. FIG. 4 illustrates the frequency steered sonar element 12transmitting a first sonar wedge 30C in the left or port direction and asecond sonar wedge 30D in the right or starboard direction. Likewise asin FIG. 3, each sonar wedge 30 in FIG. 4 is formed by one array of foursonar beams 28.

The implementations of the frequency steered sonar element 12 of FIGS. 3and 4, wherein the sonar element 12 transmits two spaced apart sonarwedges 30, each formed by four sonar beams 28, are merely exemplary. Thefrequency steered sonar element 12 may be capable of transmittinggreater or fewer numbers of sonar wedges 30, each formed by greater orfewer numbers of sonar beams 28. In addition, the spacing between eachsonar wedge 30 may vary. Furthermore, the angular size of each sonarwedge 30 may vary. Each sonar wedge 30 of FIGS. 3 and 4 may have anangular size from approximately 40 to 45 degrees. The frequency steeredsonar element 12 may be capable of transmitting a single sonar wedge 30with an angular size of up to 180 degrees.

The frequency steered sonar element 12 may also receive reflections ofthe sonar beam 28 bouncing off objects in the water and the water bed.In response, the frequency steered sonar element 12 may generate areceive electronic signal. The receive electronic signal may include oneor more single-ended electronic signals or one or more differentialelectronic signals. The type of electronic signal generated by thefrequency steered sonar element 12 may depend upon its components andarchitecture. For example, frequency steered sonar elements 12 with oneor more individual transducer elements may generate one or moresingle-ended electronic signals, while frequency steered sonar elements12 with one or more arrays of transducer elements may generate one ormore differential signals. Likewise with the transmit electronic signaland the sonar beam 28, certain characteristics of the receive electronicsignal, such as a frequency or frequency component or frequencycomponent data, correspond to similar characteristics of the reflectionsof the sonar beam 28, such that the frequency component of the receiveelectronic signal is the same frequency component as the reflections ofthe sonar beam 28. Furthermore, the frequency component of the receiveelectronic signal is an indication of the angular direction from whichthe reflections of the sonar beam 28 were received. For example, thereceive electronic signal may include a first frequency component whichindicates that the reflections of the sonar beam 28 were received from afirst angular direction. The receive electronic signal may include asecond frequency component which indicates that the reflections of thesonar beam 28 were received from a second angular direction, and soforth. The receive electronic signal may include multiple occurrences ofthe same frequency component (first, second, third, etc.) separated intime as the result of reflections of the same sonar beam 28 bouncing offof multiple objects in the water located at different distances from thefrequency steered sonar element 12. If the frequency steered sonarelement 12 transmitted a sonar wedge 30, then the receive electronicsignal may include the same number of frequency components as wereincluded in the transmit electronic signal which formed the sonar wedge30.

If the frequency steered sonar element 12 transmits a plurality of sonarwedges 30, such as the wedges 30A, 30B of FIG. 3 and the wedges 30C, 30Dof FIG. 4, then the sonar wedges 30 may be transmitted by a plurality oftransducer elements or one or more transducer arrays. The receiveelectronic signal generated by the frequency steered sonar element 12may include sonar information from all of the sonar wedges 30. Thereceive electronic signal may be communicated to an externaldestination, such as the marine sonar display device 10 of the presenttechnology.

Some implementations of the frequency steered sonar element 12 may alsoinclude electrical or electronic circuitry such as filters, amplifiers,multiplexors, digital to analog converters (DACs), analog to digitalconverters (ADCs), signal processors, or combinations thereof.

The implementations of the frequency steered sonar element 12 in FIGS. 3and 4 show the frequency steered sonar element 12 being mounted on thebottom of a hull of a marine vessel. In general, the frequency steeredsonar element 12 may be mounted anywhere on the hull below thewaterline. The frequency steered sonar element 12 may be mounteddirectly on the hull or may be attached with brackets, transom andtrolling mounts, and the like. In addition, the frequency steered sonarelement 12 may be reoriented about one, two, or three axes through theuse of a mechanism, such as a motor assembly. As an example, thefrequency steered sonar element 12 may transmit the sonar wedges 30 inthe angular directions of FIG. 3 and then be reoriented by a mechanismin order to transmit the sonar wedges 30 with the angular directions ofFIG. 4. Furthermore, the frequency steered sonar element 12 may beconfigured for towing behind the marine vessel or for use with a remoteoperated vehicle (ROV) or autonomous vehicle associated with the marinevessel.

Turning now to the marine sonar display device 10, the housing 14, asshown in FIG. 1, generally encloses and protects the other componentsfrom moisture, vibration, impact, and interference. The housing 14 mayinclude mounting hardware for removably securing the marine sonardisplay device 10 to a surface within the marine vessel or may beconfigured to be panel-mounted within the marine vessel. The housing 14may be constructed from a suitable lightweight and impact-resistantmaterial such as, for example, plastic, nylon, aluminum, or anycombination thereof. The housing 14 may include one or more appropriategaskets or seals to make it substantially waterproof or resistant. Thehousing 14 may take any suitable shape or size, and the particular size,weight and configuration of the housing 14 may be changed withoutdeparting from the scope of the present technology.

In certain embodiments, the marine sonar display device 10 may include aplurality of housings 14 if the various functions of the device 10 areseparated. For example, the display 16 and the user interface 18 may beretained in a first housing 14 to provide viewing and user interactionfunctionality, while the memory element 24 and the processing element 26may reside in a second housing (not shown in the figures) to providesignal processing functionality. Other electronic components, such asthe communication element 20 and the location determining element 22 mayreside in either one or both of the housings. In addition, some memoryand processing capabilities may be include in both housings. Electroniccommunication between the two housings may be achieved throughelectrically conductive cables or wirelessly.

The display 16, as shown in FIG. 1, may include video devices of thefollowing types: plasma, light-emitting diode (LED), organic LED (OLED),Light Emitting Polymer (LEP) or Polymer LED (PLED), liquid crystaldisplay (LCD), thin film transistor (TFT) LCD, LED side-lit or back-litLCD, heads-up displays (HUDs), or the like, or combinations thereof. Thedisplay 16 may possess a square or a rectangular aspect ratio and may beviewed in either a landscape or a portrait mode. In various embodiments,the display 16 may also include a touch screen occupying the entirescreen or a portion thereof so that the display 16 functions as part ofthe user interface 18. The touch screen may allow the user to interactwith the marine sonar display device 10 by physically touching, swiping,or gesturing on areas of the screen.

The user interface 18 generally allows the user to utilize inputs andoutputs to interact with the marine sonar display device 10. Inputs mayinclude buttons, pushbuttons, knobs, jog dials, shuttle dials,directional pads, multidirectional buttons, switches, keypads,keyboards, mice, joysticks, microphones, or the like, or combinationsthereof. Outputs may include audio speakers, lights, dials, meters, orthe like, or combinations thereof. With the user interface 18, the usermay be able to control the features and operation of the display 16 andthe marine sonar display device 10. For example, the user may be able tozoom in and out on the display 16 using either virtual onscreen buttonsor actual pushbuttons. In addition, the user may be able to pan theimage on the display 16 either by touching and swiping the screen of thedisplay 16 or by using multidirectional buttons or dials.

The communication element 20 generally allows communication withexternal systems or devices. The communication element 20 may includesignal or data transmitting and receiving circuits, such as antennas,amplifiers, filters, mixers, oscillators, digital signal processors(DSPs), and the like. The communication element 20 may establishcommunication wirelessly by utilizing radio frequency (RF) signalsand/or data that comply with communication standards such as cellular2G, 3G, or 4G, Institute of Electrical and Electronics Engineers (IEEE)802.11 standard such as WiFi, IEEE 802.16 standard such as WiMAX,Bluetooth™, or combinations thereof. In addition, the communicationelement 20 may utilize communication standards such as ANT, ANT+,Bluetooth™ low energy (BLE), the industrial, scientific, and medical(ISM) band at 2.4 gigahertz (GHz), or the like. Alternatively, or inaddition, the communication element 20 may establish communicationthrough connectors or couplers that receive metal conductor wires orcables or optical fiber cables. The communication element 20 may be incommunication with the processing element 26 and the memory element 24.

The location determining element 22 generally determines a currentgeolocation of the marine sonar display device 10 and may receive andprocess radio frequency (RF) signals from a global navigation satellitesystem (GNSS) such as the global positioning system (GPS) primarily usedin the United States, the GLONASS system primarily used in the SovietUnion, or the Galileo system primarily used in Europe. The locationdetermining element 22 may accompany or include an antenna to assist inreceiving the satellite signals. The antenna may be a patch antenna, alinear antenna, or any other type of antenna that can be used withlocation or navigation devices. The location determining element 22 mayinclude satellite navigation receivers, processors, controllers, othercomputing devices, or combinations thereof, and memory. The locationdetermining element 22 may process a signal, referred to herein as a“location signal”, from one or more satellites that includes data fromwhich geographic information such as the current geolocation is derived.The current geolocation may include coordinates, such as the latitudeand longitude, of the current location of the marine sonar displaydevice 10. The location determining element 22 may communicate thecurrent geolocation to the processing element 26, the memory element 24,or both.

Although embodiments of the location determining element 22 may includea satellite navigation receiver, it will be appreciated that otherlocation-determining technology may be used. For example, cellulartowers or any customized transmitting radio frequency towers can be usedinstead of satellites may be used to determine the location of themarine sonar display device 10 by receiving data from at least threetransmitting locations and then performing basic triangulationcalculations to determine the relative position of the device withrespect to the transmitting locations. With such a configuration, anystandard geometric triangulation algorithm can be used to determine thelocation of the marine sonar display device 10. The location determiningelement 22 may also include or be coupled with a pedometer,accelerometer, compass, or other dead-reckoning components which allowit to determine the location of the marine sonar display device 10. Thelocation determining element 22 may determine the current geographiclocation through a communications network, such as by using Assisted GPS(A-GPS), or from another electronic device. The location determiningelement 22 may even receive location data directly from a user.

The memory element 24 may include electronic hardware data storagecomponents such as read-only memory (ROM), programmable ROM, erasableprogrammable ROM, random-access memory (RAM) such as static RAM (SRAM)or dynamic RAM (DRAM), cache memory, hard disks, floppy disks, opticaldisks, flash memory, thumb drives, universal serial bus (USB) drives, orthe like, or combinations thereof. In some embodiments, the memoryelement 24 may be embedded in, or packaged in the same package as, theprocessing element 26. The memory element 24 may include, or mayconstitute, a “computer-readable medium”. The memory element 24 maystore the instructions, code, code segments, software, firmware,programs, applications, apps, services, daemons, or the like that areexecuted by the processing element 26. The memory element 24 may alsostore settings, data, documents, sound files, photographs, movies,images, databases, and the like.

The processing element 26 may include electronic hardware componentssuch as processors, microprocessors (single-core and multi-core),microcontrollers, digital signal processors (DSPs), field-programmablegate arrays (FPGAs), analog and/or digital application-specificintegrated circuits (ASICs), or the like, or combinations thereof. Theprocessing element 26 may generally execute, process, or runinstructions, code, code segments, software, firmware, programs,applications, apps, processes, services, daemons, or the like. Theprocessing element 26 may also include hardware components such asfinite-state machines, sequential and combinational logic, and otherelectronic circuits that can perform the functions necessary for theoperation of the current invention. The processing element 26 may be incommunication with the other electronic components through serial orparallel links that include universal busses, address busses, databusses, control lines, and the like.

In some embodiments, the processing element 26 may further include theelectronic circuitry of FIG. 5. In other embodiments, the processingelement 26 may be in communication with the electronic circuitry of FIG.5. The electronic circuitry may include an optional analog multiplexer(MUX) 32, an amplifier 34, a low pass filter 36, an analog to digitalconverter (ADC) 38, and a processor 40. The analog MUX 32 may includegenerally known electronic circuitry, such as a plurality oftransistor-based switches, that provide a signal selection function. Theanalog MUX 32 typically has a plurality of select control lines, aplurality of analog signal inputs, and one output. The analog MUX 32allows one of the inputs to pass through to the output. When utilizedwith the current technology, the analog MUX 32 has the receiveelectronic signals as inputs. Based on the state of the select controllines, the analog MUX 32 presents one of the receive electronic signalsat the output. When the analog MUX 32 is not included, the receiveelectronic signal is communicated directly to the amplifier 34.

The amplifier 34 may include small signal amplifier circuits as aregenerally known. The amplifier 34 may amplify the receive electronicsignal communicated from the analog MUX 32, if included. Otherwise, theamplifier 34 may amplify the receive electronic signal as received fromthe frequency steered sonar element 12. The amplifier 34 may have fixedgain or variable gain. The amplifier 34 may have a frequency responsethat filters the received electronic signal. The frequency response ofamplifier 34 may be low pass, high pass, band pass, or all pass inbehavior.

The low pass filter 36 may include filtering circuitry which passesfrequencies of a signal lower than a certain cutoff frequency andfilters frequencies greater than the cutoff, as is generally known. Thelow pass filter 36 may function as an anti-aliasing filter. Thus, thecutoff frequency may be chosen to be approximately twice the maximumfrequency component of the receive electronic signal. The low passfilter 36 may filter the receive electronic signal communicated from theamplifier 34.

The ADC 38 may include generally known circuitry capable of orconfigured to sample an analog signal and generate digital data whichcorresponds to the sampled analog values. The ADC 38 may convert thereceive electronic signal communicated from the low pass filter 36 intodigital data that may be presented in a serial or parallel stream.

The processor 40 may include DSPs, FPGAs, ASICs, or the like. In variousembodiments, the processor 40 may be the same component as, orintegrated with, the processing element 26. The processor 40 along withthe other components of FIG. 5 may perform the signal processing of thereceive electronic signals discussed below in addition to, or insteadof, the processing element 26.

By utilizing hardware, software, firmware, or combinations thereof, theprocessing element 26 may perform the following functions. Theprocessing element 26 may operate the frequency steered sonar element 12in order to receive signals and/or data that can be converted into sonarimages. In order for the frequency steered sonar element 12 to perform asweep, the processing element 26 may generate a transmit electronicsignal. As discussed above, the transmit electronic signal may includeone or more single-ended electronic signals or one or more differentialelectronic signals. The processing element 26 may be preprogrammed withthe parameters of the signal, such as frequency, etc., or may determinethe parameters based on the performance specifications of the frequencysteered sonar element 12. In some embodiments, the processing element 26may generate the transmit electronic signal as a sequence ofspaced-apart-in-time pulses, wherein each pulse is an oscillatingelectrical voltage or electrical current that includes one of aplurality of frequency components. Thus, the processing element 26 maygenerate a first pulse including a first frequency component, wait for aperiod of time, generate a second pulse including a second frequencycomponent, wait for the period of time, generate a third pulse includinga third frequency component, and so forth. For example, using thepreceding method, the processing element 26 may generate the transmitelectronic signal as a sequence of four pulses, each including adifferent frequency component. In other embodiments, the processingelement 26 may generate the transmit electronic signal as at least onebroadband pulse that includes a plurality of frequency components. As anexample, the processing element 26 may generate the broadband pulse toinclude four frequency components. The number of frequency components toinclude in the transmit electronic signal may be determined based on thespecifications of the frequency steered sonar element 12, theconstruction of the display 16, user selected settings, or the like.

With the exemplary frequency steered sonar element 12 of FIGS. 3 and 4,the processing element 26 may generate the transmit electronic signal,with either a sequence of four single frequency component pulses or abroadband pulse that includes four frequency components, which willcause the frequency steered sonar element 12 to transmit the sonar beams28 in the appropriate angular directions, so that after all of the sonarbeams 28 have been transmitted, at least one sonar wedge 30 is formed.Depending on the implementation of the frequency steered sonar element12, the processing element 26 may adjust characteristics or features ofthe transmit electronic signal, such as generating a plurality ofdifferential electronic signals with the relative phase delay betweenthe signals being adjusted, in order to determine the number of sonarwedges 30 that are transmitted and the general direction in which eachis transmitted.

The processing element 26 may communicate the electronic signal to thefrequency steered sonar element 12. The transmit electronic signal maypresent or include analog signals, digital signals, digital data, orcombinations thereof. Under normal operation, the processing element 26may repeatedly or continuously generate and communicate the transmitelectronic signal so as to ultimately produce sonar images in motion.

The processing element 26 may receive a receive electronic signal fromthe frequency steered sonar element 12 as the sonar element 12 receivesreflections of the sonar beams 28. As discussed above, the receiveelectronic signal may include one or more single-ended electronicsignals or one or more differential electronic signals. The receiveelectronic signal may include a steady stream of data or activity as theresult of receiving reflections of the sonar beams 28 from variousangular directions. Furthermore, as discussed above, the receiveelectronic signal may include a plurality of frequency components, eachof which may be associated with one of the sonar beams 28 and mayindicate the angular direction from which reflections of the sonar beam28 were received. Typically, the frequency components of the receiveelectronic signal are the same as the frequency components of thetransmit electronic signal. The processing element 26 may analyze thereceive electronic signal and determine the frequency componentsthereof. As an example, the processing element 26 may repeatedly performfrequency domain transforms, such as a fast Fourier transform (FFT), todetermine the frequency components of the receive electronic signal. Theprocessing element 26 may calculate an array of sonar data slices, eachsonar data slice including sonar data that is calculated from one of thefrequency components of the receive electronic signal. For example, eachsonar data slice may include characteristics such as an amplitude and adelay, among others, of a particular frequency component of the receiveelectronic signal. Each sonar data slice includes sonar data for onesonar beam 28 of one sonar wedge 30, and the array of sonar data slicesincludes all of the sonar data for one sonar wedge 30. The processingelement 26 generally performs the sonar data slice calculations on arepeated or continuous basis.

If two sonar wedges 30 are generated, as shown in FIGS. 3 and 4, thenthe processing element 26 may perform different operations depending onthe implementation of the frequency steered sonar element 12. Someimplementations of the frequency steered sonar element 12 may generatethe receive electronic signal upon which the processing element 26 mayperform beam forming mathematical calculations, including a complex FFT,among others, in order to determine a first array of sonar data slices,corresponding to the first sonar wedge 30A or 30C, and a second array ofsonar data slices, corresponding to the second sonar wedge 30B or 30D.

The processing element 26 may generate an array of sonar image slices 42for each sonar wedge 30. Each sonar image slice 42 may be generated froma corresponding one of the array of sonar data slices and may beassociated with the angular direction of the receive electronic signalfrom which the sonar data slice was calculated. Each sonar image slice42 may include the sonar imagery for a region of the water associatedwith the sonar beam 28 at the corresponding angular direction. Theentire array of sonar image slices 42 may include the sonar imagery forall of one sonar wedge 30.

During normal operation, the processing element 26 may repeatedly orcontinuously generate the transmit electronic signal to sweep the sonarbeam 28. In turn, the processing element 26 may repeatedly calculate thearray of sonar data slices. And, the processing element 26 mayrepeatedly generate the array of sonar image slices 42, one for eacharray of sonar data slices. In addition, the processing element 26 maycontrol the display 16 to repeatedly present the array of sonar imageslices 42, which forms a sonar wedge image 44. Since there is littledelay between the processing element 26 generating the transmitelectronic signal and the processing element 26 generating theresulting, associated sonar wedge image 44, the sonar wedge images 44may be considered “near real time”. Furthermore, the processing element26 may control the display 16 to present one near real time sonar wedgeimage 44 for each sonar wedge 30 that is transmitted by the frequencysteered sonar element 12. An example is shown in FIG. 6, wherein thedisplay 16 may present a first near real time sonar wedge image 44 for afirst sonar wedge 30 transmitted in the forward direction of the marinevessel and a second near real time sonar wedge image 44 for a secondsonar wedge 30 transmitted in the downward direction. (In FIG. 6, one ofthe sonar image slices 42 for the first near real time sonar wedge image44 is illustrated in dashed lines. The dashed lines may not normally bepresented on the display 16.)

The processing element 26 may additionally control the display 16 topresent indicia 46 to depict the marine vessel. The indicia 46 may bepositioned with regard to the near real time sonar wedge images 44 toproperly portray the relationship between the marine vessel and thesonar wedges 30. The processing element 26 may further control thedisplay 16 to present a circular grid 48 to depict the ranges ofdistance in the water from the frequency steered sonar element 12.Alternatively or additionally, the processing element 26 may furthercontrol the display 16 to present a rectangular grid.

The processing element 26 may store in the memory element 24 a pluralityof arrays of sonar data slices. In various embodiments, the processingelement 26 may store the sonar data slice arrays for a certain period oftime—say, 30 seconds, 1 minute, 2 minutes, etc. Alternatively oradditionally, the processing element 26 may store the sonar data slicearrays for a certain number of frames to be presented on the display 16.

The processing element 26 may generate a historical sonar image 50formed from the previously generated sonar image slices 42 derived fromone or more sonar beams 28. In various embodiments, the processingelement 26 may retrieve previously stored sonar data slices in order togenerate the historical sonar image 50. The processing element 26 mayfurther control the display 16 to present the historical sonar image 50.In exemplary embodiments shown in FIGS. 7A and 7B, the processingelement 26 may present one historical sonar image 50 on a portion of thedisplay 16. In some embodiments, the processing element 26 may crop aportion of one or more of the near real time sonar wedge images 44 andpresent them in a first window 52 or frame, while presenting thehistorical sonar image 50 in a second window 54. In other embodiments,the processing element 26 may not crop the near real time sonar wedgeimages 44. Alternatively, the processing element 26 may present only thehistorical sonar image 50 in the first window 52 and may not present anyof the near real time sonar wedge images 44. As shown in FIGS. 7A and7B, one sonar image slice 42 (representing the reflections from onesonar beam 28) has been selected from the downward directed near realtime sonar wedge image 44 for which the historical sonar image 50 isgenerated. Typically, the sonar image slice 42, for which the historicalsonar image 50 is generated, is highlighted on the display 16 such aswith a different color or an outline. A user may select the sonar imageslice 42 using the user interface 18, or the processing element 26 mayautomatically select the sonar image slice 42 based on various signaland/or system parameters, such as merit, sensitivity, signal to noise,orientation, beamwidth, combinations thereof, and the like. In addition,more than one adjacent sonar image slice 42 may be selected for whichthe historical sonar image 50 is generated. The sonar image slices 42may, for example, be averaged, weighted averaged, summed, or the likewhen they used to generate the historical sonar image 50.

When the processing element 26 is controlling the display 16 to presentthe historical sonar image 50, the most recently generated sonar imageslice 42 may be presented in a fixed or constant location in the secondwindow 54. Those sonar image slices 42 that were previously generatedmay scroll in the second window away from the most recently generatedsonar image slice 42 with the oldest sonar image slice 42 being farthestaway from the most recently generated sonar image slice 42. In theembodiment of FIGS. 7A and 7B, the sonar image slices 42 scroll fromright to left in the second window. In FIG. 7A, the sonar image slices42 for, say, the previous 15 seconds, or the last 50 feet that themarine vessel has traveled, are shown on the display 16, while in FIG.7B, the sonar image slices 42 for, say, the previous 30, or the last 100feet that the marine vessel has traveled, seconds are shown, with thosesonar image slices 42 from FIG. 7A having scrolled to the left.

The processing element 26 may further control the display 16 to presentone or more near real time sonar wedge images 44 and one or morehistorical sonar images 50 in the same window. When a plurality of nearreal time sonar wedge images 44 is presented, the user may select whichnear real time sonar wedge image 44 and which sonar image slice(s) 42are utilized to generate the historical sonar image 50. Alternatively,the processing element 26 may select these parameters. In the exemplaryembodiment of FIG. 8, a first near real time sonar wedge image 44projecting in the forward direction and a second near real time sonarwedge image 44 projecting in the downward direction, similar to those ofFIG. 6, are presented. (The inner boundaries of the near real time sonarwedge images 44 are shown on the display 16 in dashed lines. Theboundaries are shown here for illustrative purposes and may notnecessarily be shown during normal operation of the marine sonar displaydevice 10.) In the embodiment of FIG. 8, the processing element 26 maycontrol the display 16 to present the history of one or more sonar imageslices 42 selected from the forward projecting near real time sonarwedge image 44. The history may be presented as described above, withthe most recently generated sonar image slice 42 being presented in afixed location and the previously generated sonar image slices 42scrolling away. In other embodiments, the processing element 26 mayselect a vertical column of the sonar image, as it is shown on thedisplay 16, to fill the gap between the two near real time sonar wedgeimages 44. Thus, the processing element 26 may select a portion ofmultiple sonar image slices 42 for filling the gap. In the exemplaryembodiment of FIG. 8, the most recently generated sonar image slice 42is presented adjacent to the forward projecting near real time sonarwedge image 44 and the previously generated sonar image slices 42 scrolltoward the downward projecting near real time sonar wedge image 44.Thus, the historical sonar images may fill the gap between the two nearreal time sonar wedge images 44 and may give the appearance of having asingle near real time sonar wedge image 44 that covers a greater volumein the water than just the two separated near real time sonar wedgeimages 44. In addition, the processing element 26 may control thedisplay 16 to present the marine vessel indicia 46 and overlay the nearreal time sonar wedge images 44 and the historical sonar image 50 on thecircular grid 48.

The processing element 26 may also track the course of the marine vesselthrough data provided from the location determining element 22, oradditionally or alternatively from information from a steering or helmsystem of the marine vessel, data from accelerometers or inertialsensors associated with the frequency steered sonar element 12, or otherdevices or systems utilized with the marine vessel. When the processingelement 26 determines a change in course or heading of the marinevessel, or receives information that a course change has occurred, theprocessing element 26 may control the display 16 to remove at least aportion of the historical sonar image 50, such as the historical sonarimages 50 of FIG. 7A, 7B, or 8, so that at least part of the space onthe display 16 is at least temporarily blank. The processing element 26may resume controlling the display 16 to present the historical sonarimage 50 when a new course has been determined.

The processing element 26 may analyze the sonar data slices of any ofthe near real time sonar wedge images 44 that are being presented on thedisplay 16 to determine whether false or undesirable artifacts, or ghostimages, are included in the near real time sonar wedge images 44. Incertain embodiments, this feature may be a menu option that the user canselect to clear up the images on the display 16. The false artifacts maybe the result of reflections from downward-projecting sonar beams 28being interpreted as reflections from forward-projecting sonar beams 28.The false artifacts may also be the result of crosstalk events, such aselectrical non-isolation electrical interference, sampling mismatch whenthe analog receive electronic signals are converted to digital data,among other causes. An example of a false artifact being present in thenear real time sonar wedge image 44 is shown in the forward-projectingnear real time sonar wedge image 44 of FIG. 9A. The processing element26 may perform data subtraction, crosstalk removal algorithms, or thelike, or combinations thereof on one or more of the sonar data sliceseach time the false artifact is present to remove the false artifactfrom the near real time sonar wedge image 44. An example in the nearreal time sonar wedge image 44 after the false artifact is removed isshown in FIG. 9B.

The processing element 26 may also perform various signal processingfunctions. The processing element 26 may provide image enhancement byadjusting frequency properties of the sonar data, such as by adjustingthe data of the sonar data slices. Examples of the image enhancementprocessing may include fading by frequency, variable noise thresholds byfrequency, variable gain by frequency (including time variable gain(TVG), dynamic/automatic gain), color palette differences by frequencyband (highlighting features, highlighting recognized objects such asfish, lure, structure), combinations thereof, and the like. Suchfunctionality may provide a more normalized near real time sonar wedgeimage 44. The processing element 26 may also provide multi-frameaveraging to smooth the near real time sonar wedge images 44. Forexample, frame depth, or frame count to be averaged, may be based on themotion of the marine vessel or the frequency steered sonar element 12.Such functionality may reduce background noise to provide a more clearnear real time sonar wedge image 44. Additionally or alternatively, theprocessing element 26 may adjust some characteristic of each sonar imageslice 42, such as intensities, colors, etc. of the objects in the slice42, by weighted averaging the characteristics of the sonar image slice42 with the characteristics of the neighboring sonar image slices 42.The processing element 26 may further provide edge filtering to enablegreater image contrast and improve object identification. An example ofthe processing element 26 performing edge filtering on near real timesonar wedge images 44 is shown in FIGS. 10A and 10B. Forward-projectingand downward-projecting near real time sonar wedge images 44 undernormal conditions without edge filtering are shown in FIG. 10A. The sameforward-projecting and downward-projecting near real time sonar wedgeimages 44 with edge filtering activated are shown in FIG. 10B.

The processing element 26 may further determine the side of the marinevessel on which an object in the water is located when the frequencysteered sonar element 12 is in a forward direction and/or downwarddirection configuration. That is, the processing element 26 maydetermine whether an underwater object is in the port side of the wateror the starboard side of the water with respect to the marine vessel.The determination may be made by analyzing the signal strength, such asamplitude, intensity, energy level, etc., of the receive electronicsignals. The signal strength of the reflections of the sonar beams 28may vary according to the wobble or roll in the water of the frequencysteered sonar element 12. The wobble of the frequency steered sonarelement 12 may be the result of natural water and/or marine vesselmotion or may be artificially induced by mechanical devices. The wobblemotion and/or direction may be detected by electromechanical components,such as accelerometers and inertial sensors, that are in communicationwith the processing element 26. The direction of roll of the frequencysteered sonar element 12 may be correlated with the signal strength ofthe receive electronic signals to determine whether an underwater objectis in the port side of the water or the starboard side of the water. Insome embodiments, once the side of each detected underwater object isdetermined, the processing element 26 may generate port sonar imageslices which include underwater objects determined to be on the portside and starboard sonar image slices which include underwater objectsdetermined to be on the starboard side. The processing element 26 mayalso control the display 16 to present the port sonar image slices in afirst window and the starboard image objects in a second window. Inother embodiments, once the side of each detected underwater object isdetermined, the processing element 26 may assign a color to each objectwhen the object is presented on the display 16. For example, theprocessing element 26 may assign a first color, such as blue, to portunderwater objects, while the processing element 26 may assign a secondcolor, such as red, to starboard objects. The processing element 26 maythen control the display 16 to present one or more near real time sonarwedge images 44, wherein the underwater objects are colored aspreviously mentioned according to whether they are located in the portside of the water or the starboard side of the water.

The marine sonar display device 10 may operate as follows. The marinesonar display device 10 may be electrically connected to the frequencysteered sonar element 12 by at least one cable through which the marinesonar display device 10 may send the transmit electronic signals to thefrequency steered sonar element 12 and receive the receive electronicsignals therefrom. After the marine sonar display device 10 has beenturned on and completed a self check sequence, it may automaticallybegin transmitting the transmit electronic signal to the frequencysteered sonar element 12. The transmit electronic signal may include aplurality of frequency components—either as a single broadband pulse oras a sequence of single frequency component pulses. The transmitelectronic signal typically includes the appropriate number of frequencycomponents necessary for the frequency steered sonar element 12 totransmit a sonar wedge 30. The processing element 26 may repeatedly orcontinuously generate the transmit electronic signal and the signal mayrepeatedly or continuously be transmitted to the frequency steered sonarelement 12.

The frequency steered sonar element 12 may repeatedly or continuouslysweep the sonar beam 28, as described above, and may repeatedly orcontinuously generate a receive electronic signal which is received bythe marine sonar display device 10. The receive electronic signal mayinclude approximately the same number of frequency components as thetransmit electronic signal. Each frequency component of the receiveelectronic signal may indicate the direction from which reflections ofone of the sonar beams 28 were received. The processing element 26 maycalculate an array of sonar data slices for each sonar wedge 30 that wastransmitted into the water, wherein each sonar data slice is calculatedfrom data (such as phase, amplitude, and delay) from one of thefrequency components of the receive electronic signal. The processingelement 26 may further generate an array of sonar image slices 42 foreach array of sonar data slices, wherein each sonar image slice 42 isgenerated from one or more of the sonar data slices. One array of sonarimage slices 42 forms one sonar wedge image 44. The calculation of sonardata slices and the generation of sonar image slices 42 and in turnsonar wedge images 44 are performed repeatedly and without much delayfrom the generation of the corresponding transmit electronic signals sothat the sonar wedge images 44 are near real time sonar wedge images 44.The near real time sonar wedge images 44 may be presented on the display16, as shown in FIG. 6, wherein a forward-projecting near real timesonar wedge image 44 and a downward-projecting near real time sonarwedge image 44 are presented.

The marine sonar display device 10 may include a menu that is presentedon the display 16 and allows the user to select any of the abilities,operating modes, or options discussed above and below. The menu may beaccessed through the user interface 18 by utilizing touchscreenfunctions or hardware components such as buttons or knobs located on thehousing 14.

The marine sonar display device 10 may be operable to present historicalsonar images 50 on the display 16. As shown in FIGS. 7A and 7B, themarine sonar display device 10 may present one or more near real timesonar wedge images 44 in a first window 52 and, in a second window 54,one historical sonar image 50 derived from one of the near real timesonar wedge images 44. The historical sonar image 50 includespreviously-generated sonar image slices 42 from one of the near realtime sonar wedge images 44. The sonar image slice 42 may be selected bythe user or by the processing element 26. The previously-generated sonarimage slices 42 (in the historical sonar image 50) may scroll to theleft on the display 16, as shown in the figures, wherein the sonar imageslices 42 on the right of the second window in FIG. 7A have scrolled tothe left in the second window of FIG. 7B.

The marine sonar display device 10 may be operable to present historicalsonar images 50 on the display 16 in the same window as the near realtime sonar wedge images 44. When the marine sonar display device 10 ispresenting two near real time sonar wedge images 44, such as theforward-projecting near real time sonar wedge image 44 and thedownward-projection near real time sonar wedge image 44 with a spacetherebetween, the marine sonar display device 10 may fill the space witha historical sonar image 50 derived from the forward-projecting nearreal time sonar wedge image 44, as shown in FIG. 8.

The marine sonar display device 10 may be operable to remove falseartifacts that are included in of the one near real time sonar wedgeimages 44. An example of this ability is shown in FIGS. 9A and 9B,wherein a false artifact, possibly resulting from reflections of thewater bottom, is present in the forward-projecting near real time sonarwedge image 44 of FIG. 9A. The false artifact is removed in theforward-projecting near real time sonar wedge image 44 of FIG. 9B.

The marine sonar display device 10 may be operable to perform edgefiltering on the sonar data slices used to generate the near real timesonar wedge images 44. The edge filtering may clean up some of theclutter shown in the near real time sonar wedge images 44. An example ofthe near real time sonar wedge images 44 with edge filtering off isshown in FIG. 10A. An example of the near real time sonar wedge images44 with edge filtering on is shown in FIG. 10B.

Referring now to FIGS. 11-17, various example transducer assemblies areprovided. Specifically referring to FIGS. 12-13, a frequency steeredarray assembly 58 is illustrated having a first frequency steered arrayelement 12 a, a second frequency steered array element 12 b, and a thirdfrequency steered array element 12 c. Each of the elements 12 a, 12 b,12 c may be configured as described above with respect to frequencysteered sonar element 12. For example, each of the elements 12 a, 12 b,12 c may comprise a plurality of piezoelectric elements as describedabove.

FIG. 13 illustrates an example fan-shaped configuration of the elements12 a, 12 b, 12 c. Each of the elements 12 a, 12 b, 12 c may beconfigured as described above with respect to frequency steered sonarelement 12. Each element 12 a, 12 b, 12 c is configured to receive atransmit electronic signal, including a plurality of frequencycomponents, and to transmit an array of sonar beams into a body ofwater. Each sonar beam is transmitted in an angular direction thatvaries according to one of the frequency components of the transmitelectronic signal.

In the example of FIG. 13, end sections 64 a, 64 b, 64 c of elements 12a, 12 b, 12 c are within an intersection range 68 of each other. Theintersection range 68 is an area in which at least two of the endsections 64 a, 64 b, 64 c are positioned such that at least two distalends 70 a, 70 b, 70 c of elements 12 a, 12 b, 12 c are spaced fartherapart from each other than their corresponding end sections 64 a, 64 b,64 c. Thus, in some configurations, to create the fan-shapedconfiguration, end sections 64 a, 64 b, 64 c are each placed within theintersection range 68 so that the end sections 64 a, 64 b, 64 c are moreclosely spaced together than the distal ends 70 a, 70 b, 70 c. Theintersection range 68 may be any area which causes the end sections 64a, 64 b, 64 c to be more closely spaced together than the distal ends 70a, 70 b, 70 c. In some examples, the intersection range 68 may comprisean area up to about 20% the length of one of the elements 12 a, 12 b, or12 c. In other examples, the intersection range 68 may be defined by theprojected intersection of the longitudinal axis of each of the elements12 a, 12 b, 12 c, even when the end sections 64 a, 64 b, 64 c do notdirectly overlap.

In some configurations, end sections 64 a, 64 b, 64 c overlap to createthe fan-shaped configuration. Thus, for example, end sections 64 a, 64b, 64 c may lie in the same horizontal plane while the longitudinal axisof one or more of the elements 12 a, 12 b, 12 c deviates from thathorizontal plane. For example, the longitudinal axis of at least two ofthe frequency steered transducer array elements can be spacedhorizontally apart and rotated vertically at least 15 degrees, at least20 degrees, or by any amount to achieve a desired field-of-view asdescribed below. In the example of FIG. 13, the longitudinal axis ofelements 12 a, 12 b, 12 c are rotated by approximately 22.5 degrees. Endsections 64 a, 64 b, 64 c comprise up to 30 percent of the length of theelements 12 a, 12 b, 12 c. In some configurations, end sections 64 a, 64b, 64 c comprise up to about 15 percent of the length of the elements 12a, 12 b, 12 c.

The fan-shaped configuration of FIG. 13 provides improved laminar flowover conventional stacked x-configurations. The elements 12 a, 12 b, 12c do not “jut out” ahead of each other so water flow is not disrupted onthe face of any element 12 a, 12 b, 12 c. A hydrodynamic endcap may beplaced on the leading square ends of the elements 12 a, 12 b, 12 c tofurther improve flow. Additionally, mechanical and electrical attachment(and other assembly processes) of the transducer assembly and itscomponents are greatly simplified with all elements 12 a, 12 b, 12 c inone plane.

The example configuration of FIG. 13 enables the generation of afield-of-view 62 like that illustrated in FIG. 11, while providingimproved hydrodynamic characteristics when compared to conventionalstacked x-configurations. Each of the elements 12 a, 12 b, 12 c can beconfigured to transmit an array of sonar beams in angular directionsthat form a sonar wedge. Those sonar wedges combine to formfield-of-view 62.

FIGS. 14A and 14B illustrate example fields-of-view 62 for the assemblyconfigurations of FIGS. 12 and 13. In the illustrated exampleconfigurations, a near-continuous field of view 62 is provided by thearray assembly 58 without requiring the stacking of arrays. Because theorigin of the sonar beams are slightly offset array-to-array, it can bedesirable to slightly overlap the wedges and use graphical techniques(such as blending) to deal with the borders between sectors. However,the array elements 12 a, 12 b, 12 c may be positioned in anyconfiguration to increase or decrease the amount of overlap of thewedges to generate any desired field-of-view.

In the example of FIG. 14B, element 12 a generates wedges 30 e, element12 b generates wedges 30 f, and element 12 c generates wedges 30 g.Wedges 30 e, 30 f, 30 g form field-of-view 62 to generate a desiredregion of sonar coverage. In configurations, the sonar wedges 30 e, 30f, 30 g generated by the elements 12 a, 12 b, 12 c generate afield-of-view 62 of at least 60 degrees, a field-of-view of at least 90degrees, or any amount to achieve a desired coverage region. In theexample of FIGS. 14A and 14B, the field-of-view 62 is at least 130degrees. A field-of-view such as 130 degrees, or even generallyexceeding 90 degrees, can be desirable in various boat-mountedconfigurations to provide forward-looking sonar coverage in addition tocoverage underneath the boat.

In the fan-shaped configuration of FIG. 13, the end sections 64 a, 64 b,64 c overlap while the longitudinal axis of one or more of the elements12 a, 12 b, 12 c is vertically varied (e.g., 10 degrees, 20 degrees,22.5 degrees, 30 degrees, etc) to determine the alignment of the variouswedges 30 e, 30 f, 30 g. However, any number of elements 12, wedges 3,and vertical alignments may be employed to create any desiredfield-of-view 62.

In other configurations, fewer than three, or more three, elements 12may be utilized with a partially-stacked configuration. If theapplication calls for a balance between drag profile and overall productdimensions, compromised arrangements are possible such as the trianglearrangement illustrated in FIG. 15.

Referring to FIG. 16-17, a housing 60 is illustrated including the arrayelements 12 a, 12 b, 12 c. Elements 12 a, 12 b, 12 c are positionedwithin housing 60 to enable the housing 60 to present a shape andconfiguration suitable for mounting on the underside of a boat withoutimpacting boat or sonar performance. That is, the fan arrangement ofelements 12 a, 12 b, 12 c within housing 60 allows the housing 60 tostay in the water while elements 12 a, 12, 12 c continue ensonifying andimaging the scene under the boat, even when the boat is in motion and“on plane”.

In configurations, housing 60 is triangular shaped and configured to beaffixed to the transom of a boat. Housing 60 may include housingsections 66 a (labeled GARMIN™), 66 b, 66 c. Housing sections 66 a, 66b, 66 c respectively house elements 12 a, 12 b, 12 c. Housing sections66 a, 66 b, and 66 c are sized to the dimensions of elements 12 a, 12 b,12 c to minimize lensing and other undesirable beam distortions that maybe created by excessive plastic and housing materials in front of thetransmitting face of each element 12 a, 12 b, 12 c. Housing sections 66a, 66 b, and 66 c additionally enable housing 60 to present astreamlined configuration, where the width of housing 60 is minimizedwhile presenting a laminar configuration. Housing 60 may include variousmounting apertures and connecting elements to allow the housing 60 to beaffixed to the transom of a boat. In such transom-mountedconfigurations, housing sections 66 a, 66 b, and 66 c and the resultinglow-drag configuration allow assembly 58 to remain in the water whilethe boat maneuvers—even at speed—without creating undesirable drag orinterference. That is, in various configurations, housing 60 andsections 66 a, 66 b, 66 c enables assembly 58 to be utilized at speedsexceeding 10 mph, or even 40 mph. Housing 60 may additionally oralternatively be configured for mounting to a trolling motor, formounting to a pole, for mounting through a boat's hull, for towfishmounting, for mounting to a remotely-operated vehicle (ROV),combinations thereof, and the like.

Although the technology has been described with reference to theembodiments illustrated in the attached drawing figures, it is notedthat equivalents may be employed and substitutions made herein withoutdeparting from the scope of the technology as recited in the claims.

Having thus described various embodiments of the technology, what isclaimed as new and desired to be protected by Letters Patent includesthe following:
 1. A transducer assembly comprising: a triangular-shapedhousing including a first housing section, a second housing section, anda third housing section arranged in a fan-shaped configuration; and aplurality of frequency steered transducer array elements positionedwithin the housing, each of the transducer array elements including aplurality of piezoelectric elements, the plurality of frequency steeredtransducer array elements including a first element positioned with thefirst housing section, a second element positioned within the secondhousing section, and a third element positioned with the third housingsection, wherein each of the housing sections are sized to thedimensions of the respective frequency steered transducer array elementshoused therein, wherein each frequency steered transducer array elementis configured to receive a transmit electronic signal including aplurality of frequency components and to transmit an array of sonarbeams into a body of water, each sonar beam transmitted in an angulardirection that varies according to one of the frequency components ofthe transmit electronic signal, wherein the frequency steered transducerarray elements are positioned within the housing in a fan-shapedconfiguration where an end section of at least two of the frequencysteered transducer array elements are within an intersection range ofeach other, wherein the longitudinal axis of at least two of thefrequency steered transducer array elements are spaced horizontallyapart and rotated vertically between approximately 20 and 30 degrees. 2.The transducer assembly of claim 1, wherein each of the frequencysteered transducer array elements are configured to transmit an array ofsonar beams in angular directions that form a sonar wedge.
 3. Thetransducer assembly of claim 1, wherein the sonar wedges generated bythe frequency steered transducer array elements generate a field-of-viewof at least 60 degrees.
 4. The transducer assembly of claim 3, whereinthe field-of-view is at least 90 degrees.
 5. The transducer assembly ofclaim 4, wherein the field-of-view is at least 130 degrees.
 6. Thetransducer assembly of claim 1, wherein the housing is configured to beaffixed to a transom of a boat.
 7. The transducer assembly of claim 1,wherein the end sections of the frequency steered transducer arrayelements overlap.
 8. A transducer assembly comprising: atriangular-shaped housing including a first housing section, a secondhousing section, and a third housing section arranged in a fan-shapedconfiguration; and a plurality of frequency steered transducer arrayelements positioned within the housing, each of the transducer arrayelements including a plurality of piezoelectric elements, thelongitudinal axis of the frequency steered transducer array elementsspaced horizontally apart and rotated vertically between approximately20 and 30 degrees, the plurality of frequency steered transducer arrayelements including a first element positioned with the first housingsection, a second element positioned within the second housing section,and a third element positioned with the third housing section, whereineach of the housing sections are sized to the dimensions of therespective frequency steered transducer array elements housed therein,wherein each frequency steered transducer array element is configured toreceive a transmit electronic signal including a plurality of frequencycomponents and to transmit an array of sonar beams into a body of water,each sonar beam transmitted in an angular direction that variesaccording to one of the frequency components of the transmit electronicsignal, wherein the transmitted sonar beams form a plurality of sonarwedges that generate a field-of-view of at least 60 degrees, wherein thefrequency steered transducer array elements are positioned within thehousing in a fan-shaped configuration where an end section of each ofthe frequency steered transducer array elements overlap.
 9. Thetransducer assembly of claim 8, wherein the field-of-view is at least 90degrees.
 10. The transducer assembly of claim 9, wherein thefield-of-view is at least 130 degrees.
 11. The transducer assembly ofclaim 8, wherein the housing is configured to be affixed to a transom ofa boat.